Carbonyls and Carboxylic Acids Flashcards
(130 cards)
1
Q
Where is the C=O situated in an aldehyde?
A
At the end of carbon chain
2
Q
What is the number of the carbon with the =O in an aldehyde?
A
1
3
Q
where is the C=O situated in a ketone?
A
Somewhere along the carbon chain
BUT NEVER AT THE END
4
Q
What number should the C=O have in a ketone?
A
The lowest number
5
Q
What are primary alcohols oxidised to?
A
Aldehydes
Carboxylic acids
6
Q
What are secondary alcohols oxidised to?
A
Ketones
7
Q
How do you oxidise a primary alcohol to a aldehyde?
A
Distillation
8
Q
How do you oxidise a primary alcohol to a carboxylic acid?
A
Reflux
9
Q
What are the two products of oxidising an alcohol?
A
Aldehyde/carboxylic acid/ketone + water
10
Q
What are the conditions needed to oxidise a primary alcohol to an aldehyde?
A
Heat
Potassium dichromate
Excess of primary alcohol
11
Q
Why do you need an excess of alcohol when oxidising a primary alcohol to a aldehyde?
A
So doesn’t further oxidise to a carboxylic acid
12
Q
What colour does potassium dichromate turn when an alcohol has been oxidised?
A
Orange —-> green
13
Q
What are the conditions needed to oxidise a primary alcohol to an carboxylic acid?
A
Heat
Excess [o] (potassium dichromate)
Primary alcohol
14
Q
Why do you need an excess of [o] when oxidising a primary alcohol to a carboxylic acid?
A
To ensure the reaction is complete
15
Q
What will not be produced if a carboxylic acid is produced via further oxidation?
A
Water
16
Q
How can secondary alcohols be oxidised?
A
Distillation or reflux
17
Q
What are the conditions needed for oxidising a secondary alcohol?
A
Heat
Excess [o]
Secondary alcohol
18
Q
What can aldehydes be reduced to?
A
Primary alcohol
19
Q
What is reducing agent is to reduce a ketone/aldehyde?
A
NaBH4/H2O
20
Q
What is the name of NaBH4?
A
Sodium tetrahydrioborate
21
Q
Why is the NaBH4 important?
A
Contains BH4 - which is the source of H- (hydride ion)
22
Q
What are ketones and aldehydes reduced to?
A
Respective ion
23
Q
What are the conditions needed for the reduction of ketones and aldehydes?
A
Warm it using ethanol or water as a solvent
24
Q
What is the difference between an oxidising and reducing reaction?
A
Oxidising - [O]
Reducing =[H]
25
What are the products of reducing a ketone and aldehyde?
Just the alcohol
26
What happens in a carbonyl reaction?
Add hydrogen cyanide across C=O of aldehydes + ketones
27
Describe hydrogen cyanide
Colourless liquid
| Extremely poisonous
28
What is the problem with HCN?
Cannot be safely used
29
What can be used instead to combat the problems of HCN?
Sodium cyanide for cyanide ion
Use H2SO4 for hydrogen ion
STILL VERY DANGEROUS
30
Why is using HCN very useful?
Increases the length of the carbon chain
31
What does the reaction of carbonyls with HCN produce?
Hydroxy nitrile
32
How do you name a hydroxy nitrile?
Need to include C on CN as part of longest chain
OH must be smallest number
eg. 2-hydroxybutanenitrile
33
What does tollens reagent do?
Oxidise aldehydes to carboxylic acids
34
What does tollens not oxidise?
Ketones
35
Describe the process of using tollens reagent
```
NaOH(aq) added to AgNO3
Until brown precipitate forms
Then add dilute NH3 until ppt dissolves to form colourless solution
Then add chemical and heat
Positive result = silver mirror
```
36
What is the positive result for tollens reagent?
Silver mirror
37
What is the equation for a positive result using tollens reagent?
Ag(aq) + e- ----> Ag(s)
38
What does 2,4 DNP react with?
Carbonyls
39
What is important about 2,4 DNP?
It only reacts with carbonyl with a C=O bond
40
What does 2,4 DNP not react with then if it only reacts with carbonyls with a C=O bond?
Carboxylic acids
| Esters
41
Which carbonyls does 2,4 DNP react with?
Aldehydes
| Ketones
42
What does 2,4 DNP form when it reacts with carbonyls?
Orange precipitate
43
What is 2,4 DNP dissolved in?
Methanol + H2SO4
44
What is orange precipitate produced in carbonyl reaction with 2,4 DNP?
Derivative of the carbonyl
45
What can 2,4 DNP used to do?
Identify unknown compounds with a carbonyl group
46
What is the method for identifying carbonyls?
Add 2,4 DNP = orange ppt = derivative
Filter off crystals using Buchner funnel + water pump
Purify = dissolve crystals in smallest amount of hot solvent (ethanol)
Then put test tubes in ice water to recrystalise pure solid
Filter off crystals using a Buchner funnel + water pump
Find melting point of pure solids
Compare to known database of melting points for carbonyl derivatives
47
Why are the first set of crystals dissolved in carbonyl identification method?
Because they were impure and need a pure solid to identify melting point
48
What are the bonds arranged in a carboxylic acid?
Planar
49
How do you name a carboxylic acid?
Select longest chain of C atoms (containing COOH)
| Number chain starting from end closest COOH
50
What is the name of a carboxylic acid with a 4 carbon chain?
Butanoic acid
51
Why is a carboxylic acid polar?
As electrons drawn towards O
52
Why are carboxylic acids soluble in water?
H bonds form between H + O atoms on molecule
53
Why does as the chain increases the solubility of carboxylic acid decreases?
Due to non-polar carbon chain having a greater effect on polarity overall
54
What type of acid is a carboxylic acid?
Weak acid
55
What is the ion formed called in reactions with carboxylic acids?
Carboxylate ion
56
What is the formula of a methanoate ion?
HCOO-
57
What is the formula of a ethanoate ion?
CH3COO-
58
What is the formula of a propanoate ion?
CH3CH2COO-
59
What ion is form when a carboxylate ion joins with a benzene ring?
Benzoate ion
60
Why are the reactions with carboxylic acids redox reactions?
Because the hydrogen on the carboxylic acid goes from +1 to 0
61
What are the products of ethanoic acid + sodium?
Sodium ethanoate + hydrogen
62
What are the products of methanoic acid + sodium hydroxide?
Sodium methanoate + water
63
What are the products of propanoic acid + calcium carbonate?
Calcium propanoate + water + carbon dioxide
64
What is the problem with adding Na to acids?
Dangerous
| Sodium ethanoate = not nice
65
But what else can Na react with?
Alcohols
66
What are the products of ethanol + sodium?
Sodium ethoxide + hydrogen
67
What is a carboxylic acid derivative?
A compound that can be hydrolysed to form the patent carboxylic acid it was formed from
68
What do all CA derivatives have in common?
A common sequence of atoms in their structure known as an acyl group
69
What are the CA derivatives?
Ester
Acyl chloride
Acid anhydride
Amide
70
What is esterification?
Carboxylic acid + alcohol ----> ester + water
71
What type of reaction is esterification?
Condensation reaction
72
What are the conditions needed for esterification?
H2SO4 catalyst
| WARM conditions
73
Why are esters useful?
Make pleasant odours
74
What are esters used for?
Perfumes
75
What are products of propanoic acid + ethanol?
Ethyl propanoate + water
76
How is an acid anhydride formed?
When H2O is removed from 2 molecules of carboxylic acid
77
How do you name an acid anhydride?
Acid + anhydride
| eg. Ethanoic anhydride
78
What is another way to form an ester?
Acid anhydride + alcohol ----> ester + carboxylic acid
79
What are the products of propanoic anhydride + ethanol?
Ethyl propanoate + propanoic acid
80
What is hydrolysis?
The chemical breakdown of a compound in the presence of water or in an aqueous solution
81
What are the two types of hydrolysis?
Acid hydrolysis
| Alkaline hydrolysis
82
What are the conditions needed for acid hydrolysis?
Heated under reflux with dilute aqueous acid
Acid catalyst (HCl (aq))
Reversible reaction
83
What is the general equation for acid hydrolysis?
Ester + water ----> carboxylic acid + alcohol
| Reversible reaction
84
What are the conditions needed for alkaline hydrolysis?
Reflux with aqueous alkali (NaOH/KOH)
| Irreversible reaction
85
What is the general equation for alkaline hydrolysis?
Ester + NaOH ----> carboxylate salt + alcohol
86
What can the salt produced in alkaline hydrolysis be used to make?
Soap
87
What products are produced in the acid hydrolysis of methyl ethanoate + water?
Ethanoic acid + methanol
88
What products are produced in the alkaline hydrolysis of methyl ethanoate + NaOH?
Sodium ethanoate + ethanol
89
How do you name acyl chlorides?
Add "oyl chloride" for COCl part
| No. C atoms from C with acyl
90
What is called when a benzene ring is attached to COCl?
Benzoyl chloride
91
What is the name of CH3CH2COCl?
Propanoyl chloride
92
What can amines be classed as?
Primary, secondary or tertiary
93
If the NH2 is on the end carbon what is the suffix?
Amine
94
What is the name of CH3NH2?
Methylamine
95
If the NH2 is on any other carbon than carbon one what is the prefix?
Amino
96
If the prefix is amino what must you do when naming it?
You must number the carbon the amino appears on
97
What is the name of CH3CHNH2CH3?
2-amino propane
98
In secondary and tertiary amines how are they named different?
The suffix is always amine
Name alphabetically
Must use "N" to symbolise it is attached to the N
eg. N,N - dimethylamine
99
What can amides be classes as?
Primary, secondary or tertiary
100
What do amides contain?
Double bond O
101
How do you name amides?
Suffix = always amide
102
What must you do when naming a secondary or tertiary amide?
Include "N" in the name
103
What is the name of CH3CH2CONH2?
Propanamide
104
What is it called when a benzene ring is joined to a amide group?
Benzamide
105
What is the name of CH3CH2CH2CONHCH2CH3?
N- ethyl butanamide
106
How is an acyl chloride made?
By reacting carboxylic acid + thionyl chloride
107
What is the formula of thionyl chloride?
SOCl2
108
What is formed when you reaction propanoic acid + thionyl chloride?
Propanoyl chloride + sulphur dioxide + HCl
109
What is the general formula for synthesis of an acyl chloride?
Carboxylic acid + thionyl chloride ----> acyl chloride + SO2 + HCl
110
What will be produced in the synthesis of an acyl chloride?
Steamy white fumes
111
When you react an acyl chloride + alcohol what will the products be?
Ester + HCl
112
Describe the reaction of an acyl chloride + alcohol?
Vigorous reaction at R.T
113
What products are formed when propanoyl chloride + propanol?
Propyl propanoate + HCl
114
What will be produced in the reaction of acyl chloride + alcohol?
Steamy white fumes
115
When you react an acyl chloride + phenol what will the products be?
Aromatic ester + HCl
116
What is different about the reaction between phenol + acyl chloride?
Reversible reaction
117
What will be produced in the reaction of acyl chloride + phenol?
Steamy white fumes
118
When you react an acyl chloride + water what will the products be?
Carboxylic acid + HCl
119
Describe the reaction of acyl chloride + water
Vigorous reaction with cold water
120
What products are formed when propanoyl chloride + H2O?
Propanoic acid + HCl
121
What will be produced in the reaction of acyl chloride + water?
Steamy white fumes
122
When you react an acyl chloride + ammonia what will the products be?
Amide + ammonium chloride
123
Describe the reaction of acyl chloride + ammonia
Violent reaction at R.T to form a primary amide
124
What products are formed when propanoyl + NH3?
Propanamide + NH3Cl
125
When you react an acyl chloride + amine what will the products be?
Amide + alkyl (eg. methyl)ammonium chloride
126
Describe the reaction of acyl chloride + amine
Violent reaction at R.T to form a secondary amide
127
What products are formed when propanoyl + methylamine?
N- methyl propanamide + methyl ammonium chloride
128
Which acyl chloride reaction produces a primary amide?
Acyl chloride + NH3
129
Which acyl chloride reaction produces a secondary amide?
Acyl chloride + amine
130
Which acyl reactions don't produce steamy white fumes and why?
NH3
Amine
Because HCl isn't produced
